Mechanism for grinding artificial dentures



Jan. 18, 1938.

L. N. ROEBUCK ET AL MECHANISM FOR GRINDING ARTIFICIAL DENTURES FiledNOV. 17, 1936 Patented Jan. 18, 1938 MECHANISM FOR- GRINDING "ARTIFICIALDENTURES Leslie Norman Roebuck, Melbourne, Australia, and Samuel JamesEverett, Thornton Heath, England; said Everett assigncr to said RoebuckApplication November 17, 1936, Serial No. 111,326 In Great BritainDecember 5, 1935 8 Claims.

This invention concerns improvements in or relating to mechanism forgrinding or finishing the teeth of artificial dentures of the kind inwhich one of the dentures is given a bodily rotary motion. By a bodilymotion, in this specification, is meant a motion of translation, ofwhich all parts of the carrier partake more or less in the same measure,as distinct from revolution about a single central axis. In mechanismsof this kind known or proposed heretofore, a bodily rotary motion hasbeen imparted to a carrier for the denture with the assistance of aneccentric driving device and some form of guiding means. It is an objectof the invention to provide an improved or simplified mechanism of thekind set forth.

According to the invention, grinding mechanism of the kind set forthcomprises, in combination with driving means for the denture-carrier,resilient guiding means adapted for permitting the said carrier torotate bodily whilst preventing revolution thereof about its axis.Preferably the said resilient guiding means is arranged in such mannerthat the carrier tends to be moved by the driving means with a bodilycircular motion.

Thus, a rotary crank or eccentric may be pro vided for driving thecarrier and the latter may be guided upon a support by means of anannular resilient coupling which surrounds the crank or eccentric andconnects the carrier to the support in such fashion as to hold thecarrier against revolution whilst permitting it to be rotated bodily,with a substantially circular motion, by the crank or eccentric.

Grinding mechanism in accordance with the invention may conveniently beincorporated in an articulator, particularly in an articulator of theconstruction described in the United States Patent No. 2,061,484 inplace of the grinding mechanism illustrated in that patent. Anembodiment of the invention devised more particularly for incorporationin such an articulator will now be described by way of example and withreference to the accompanying drawing, in which:-

Fig. 1 is a perspective view of the articulator and grinding mechanism,

Fig. 2 a transverse vertical section through the grinding mechanism, and

Fig. 3 a plan view of the said mechanism, as seen from below, with thecarrier removed.

In the drawing, the support I for the grinding mechanism is illustratedas the upper frame- 5 member of the aforesaid articulator. Secured tothesupport l is a cylindrical bearing 2 for a r0- tatable cylindrical body3 which is conveniently formed in one piece with a driving member which,as shown, is a pulley 4. The latter is arranged to bear upon the upperend of the bearing 2. The cylindrical body 3 has an eccentric bore 5through which projects a pin 6 having a carrier 1 for the upper denturescrewed upon its lower end. The carrier may have the form of a flangedplate and may be provided with clamping screws 8 for engaging posts 8which projects up Home. removable ring 1 into holes in the plate 7. Thepin 6 passes right through the cylindrical body 3 and bears with itshead 9 on the pulley 4. By this means, the carrier i is firmly, althoughdetachably, secured in relation to the support I.

A soft rubber ring it is arranged around the periphery of the spacebounded by the support I and carrier 1 and the abutting flanges l2, l3thereon. The ring ll overlaps both of the flanges (Fig. 2). The supportand carrier are provided respectively with pins. it, l5 which projectinto alternate holes it, i"! in the rubber ring H. This arrangementconstitutes the resilient guiding means or coupling. The pins l4, l5should be substantially evenly spaced around the ring, so that theyresiliently locate the carrier, 1. e. permit the carrier to be moved ashort, distance in its own plane with equal freedom in all directions,but prevent the said carrier from being revolved about its central axis.In other words a definite preset orientation of the carrier 1 inrelation to the support I is maintained by the resilient guiding meansor coupling, The rubber ring l l is preferably slightly compressedbetween successive pins H3 or 55 on the support or carrier.

When the cylindrical body 3 is rotated by driv: ing the pulley t, thepin 6 is carried round; in a circular path by the eccentric bore 5. Onaccount of the above-described arrangement of the. rubber ring I l, thecarrier '5 cannot revolve about its axis. The resilience of the saidring, however, permits the carrier to follow the motion of the pin by abodily or translatory circular motion. As will be understood, thecircular motion of the carrier 1 is of small amplitude suitable foreffecting a grinding action between the surfaces of the upper denturecarried thereby and those of the lower denture carried on a fixed lowersupport, but is insufficient for causing destruction of the cusps of theteeth. Such circular motion of the carrier 1 gives a generally efiectivegrinding action, but it will be appreciated that the motion performed bythe said carrier may not always be perfectly circular, as the draggingaction of the teeth upon one another during grinding may modify themotion to a greater or less extent. The resultant grinding action maythus adapt itself in some measure to the varying conditions duringgrinding.

The necessary movements of the teeth corresponding to movements thereofwhich occurin natural chewing are effected manually. As described in theabove-mentioned specification,

for instance, the upper and lower dentures are mounted in correctrelative positions in the articulator and the upper frame-member l ofthe said articulator is moved during the grinding process. In thearticulator illustrated, this is effected by adjusting the screws IS.The latter act upon the frame-pivots I9 which are guided in the slots 20and are also acted upon by springs 2!. By this means, movements ofnatural chewing can be simulated, so as to ensure that the finishedteeth will be free from any tendency to lock together in any positionwhen in use.

To permit of the carrier 1 being secured in a predetermined positioncorresponding to central occlusion of the dentures, a locking pin, forexample a set-screw 22, is mounted in the cylindrical bearing 2 and isadapted. for being engaged in a recess 23 in the cylindrical body 3 whenthe latter is in the position corresponding to central occlusion. Thesaid recess and the extremity of the screw entering it are preferablymade of rounded or conical shape, as shown, so that the act oftightening the screw will force the cylindrical body 3 accurately intothe position corresponding to control occlusion. An initial approximatepositioning is performed by rotating the pulley 4 until an arrow 4thereon points to the rear. An oiling duct is indicated at 24 and aloading weight at 25.

Various modifications may be made within the scope of the invention: Therubber ring may engage in formations on or in the support and carrier,for example circular grooves therein: More than one rubber ring may beprovided: The ring may be compressed between the support and carrier:The grinding mechanism described may obviously be incorporated in ormounted on articulators constructed differently from that described inthe aforesaid specification.

The above described locking means 22, 23 may permit a slight oscillatorymotion of the carrier 1. If it is desired that even this motion shouldbe excluded, provision may also be made for locking the carrier 1 to theframe I by means of a screw which passes through a large hole in thelatter, behind the bearing 2, and engages in a tapped hole in theformer, the head of the screw bearing upon the frame I by way of awasher.

We claim:-

1. Denture-grinding mechanism comprising, in combination with adenture-carrier and driving means therefor, resilient guiding means forthe said carrier adapted for permitting the carrier to be rotated bodilyby the driving means whilst preventing revolution of the said carrierabout its axis.

2. Denture-grinding mechanism comprising, in combination with adenture-carrier and driving means therefor, a support and a flexiblering arranged between the said carrier and support and adapted forpermitting the carrier to be rotated bodily by the driving means whilstpreventing revolution of the said carrier about its axis.

3. Denture-grinding mechanism comprising a support, a denture-carrier,rotary driving means for the said carrier, a flexible coupling ringlocated between the support and the carrier, and means for anchoring thesaid ring at intervals to the support and carrier.

4. Denture-grinding mechanism comprising a support, a denture carrier,rotary driving means for the said carrier, a flexible coupling ringlocated between the support and the carrier and formed with apertures atintervals, and anchoring bodies provided on the support and carrier andextending from the said support and carrier into alternate apertures inthe flexible coupling 4 ring.

5. Denture-grinding mechanism comprising a support, a denture carrier,rotary driving means for the said carrier, a flexible coupling ring.located between the support and the carrier, and means for locating thesaid carrier in relation to the said support, the flexible coupling ringbeing under an initial compression between the support and the carrierlocated thereon.

6. Denture-grinding mechanism comprising a support, a denture-carrier, arotatable body with an eccentric bore, a pin extending into the saidbore and connected at its lower end to the carrier and supported at itsupper end by the rotatable body, and a. flexible coupling means locatedbetween the said carrier and the support and adapted for permitting theformer to rotate bodily but not to revolve in relation to the saidsupport.

7. Denture-grinding mechanism comprising a support, a denture-carrier,rotary driving means for the said carrier, resilient guiding meansbetween the said support and carrier adapted for permitting bodilyrotation of the carrier, and locking. means for securing the carrier inrelation to the support in the position corresponding to centralocclusion.

8. Denture-grinding mechanism according to claim 7, wherein the lockingmeans comprises a set-screw with a shaped extremity engageable in acomplementary recess in a rotatable part of the driving means.

LESLIE NORMAN ROEBUCK. SAMUEL JAMES EVERETT.

